The concept of avoidable mortality leads to an attempt at using specific mortality rates as output measures of health services. The analysis covered 43 Belgian districts between the years 1974 and 1978. Two Belgian areas were compared along a dimension defined by two axes of a correspondence factor analysis: Flanders which is associated with low SMR of avoidable mortality and Wallonia which has high rates. The persistence of high mortality in Wallonia was confirmed. Factorial scores for each district were used as indexes for geographical heterogeneity. Variations in these indices, including patient consultation rates and technical medical procedures, remained even after adjustment for socio-economic differences.